1. Field of the Invention
The present invention pertains to patient interface devices and more particularly to eliminating undesirable consequences caused by continuous, repeated, and/or excessive pressure associated with wearing patient interface devices.
2. Description of the Related Art
There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas to the airway of a patient. For example, it is known to deliver a flow of breathing gas to a patient during at least a portion of the breathing cycle to treat breathing and/or cardiac disorders such as obstructive sleep apnea syndrome, chronic obstructive pulmonary disease, congestive heart failure, respiratory distress syndrome, and other breathing and/or cardiac disorders.
Generally, a pressure generating device is employed to produce the flow of breathing gas which is delivered to a patient interface device via a patient conduit. The patient interface device is in fluid communication with, and is structured to deliver the flow of breathing gas to, the airway of the patient.
The patient interface device may be, for example, a nasal mask, full-face mask (i.e., a nasal/oral mask), or a total face mask structured to be placed on and/or over the face of the patient. The patient interface device typically includes a mask cushion and shell. The patient interface device may also include, for example and without limitation, a forehead support, a chin support, and/or a cheek support. Each of these supports may have an associated cushion which comes in contact with the patient's face. A headgear assembly, which typically contacts the back and/or top of the patient's head, may be employed to secure the patient interface device to the patient.
Upon contact with the patient's face, the mask cushion deforms slightly creating a seal between the patient interface device and the patient's face. This seal minimizes leakage of the flow of breathing gas being delivered to the airway of the patient. To insure an adequate seal, a patient undergoes a fitting procedure in which the proper size and style of patient interface device is selected. Generally, the patient wears the selected patient interface device until normal wear and tear necessitates that a replacement device be ordered (e.g., every six months to one year). Most patients receive the same size and style mask as a replacement device.
The cushions (e.g., for the mask and supports) are structured to provide a contact footprint relative to the face of such a patient and the headgear assembly is structured to provide a contact footprint relative to the head of such a patient. The term “contact footprint” refers to the portion of the face/head that is contacted by the cushions/headgear, and the immediate surrounding area, when the patient interface device and/or headgear assembly are being worn by the patient. Pressure exerted on the patient's face is generally localized to the contact footprint associated with the cushions and pressure exerted on the top/back of the patient's head is generally localized to the contact footprint associated with the headgear assembly. Because a patient is generally fitted with a single size/style of patient interface device and headgear assembly, the patient is repeatedly exposed to pressures exerted by the patient interface device and headgear assembly at the same locations (i.e., at the contact footprints associated with the patient interface device and headgear assembly).
Continuous, repeated, and/or excessive pressure applied at a contact footprint may cause undesirable consequences. For example, excessive pressure exerted by the mask cushion may cause a patient's skin to breakdown at the contact footprint associated with that cushion. More serious developmental problems may arise for neonatal, infant, and pediatric patients whose facial and cranial contours are dynamic due to growth of the child. For example, pressure exerted by the mask cushion on neonatal, infant, and pediatric patients may cause facial and bone deformation at or near the contact footprint associated with that cushion.
Accordingly, a need exists for an apparatus and method for providing improved comfort for a patient receiving a flow of breathing gas which overcomes these and other problems associated with known systems.